1. Field of the Invention
This invention relates to a circuit arrangement for storing information in a programmable ECL read only memory, in which the storage elements consists of a circuit element and an interruptable resistor which are arranged between the row and column lines, and in which the interruption of the resistors takes place by means of an externally specified current, and in which a row switch is provided for each row line and consists of a differential amplifier having operating transistors connected in parallel and activated by address signals, and a reference transistor, and which also consists of an emitter follower connected to the collectors of the operating transistors and to a row line.
2. Description of the Prior Art
In programmable read only memories, in ECL technology, storage elements are arranged in a matrix form between row lines and column lines. The storage elements consist of a circuit element and an interruptable resistor. The circuit element, for example, may be a transistor or a diode. The interruptable resistor, for example, consist of NiCr. If the programmable read only memory is to have information stored therein, the resistors must be interrupted corresponding to the information which is to be stored. For example, a binary "1" corresponds to an interrupted resistor; a binary "0" corresponds to a non-interrupted resistor. Interruption of the resistors takes place by passing a correspondingly great externally specified current through the resistors. This is made possible to applying a correspondingly large voltage to the storage elements, and effecting a through connection of the circuit elements.
Therefore, a special circuit arrangement is necessary in order to input information into the programmable read only memory. If, for example, the storage elements are realized by means of a transistor and a storage resistor located in the emitter branch of the transistor, then, with the aid of such a circuit arrangement, a voltage is applied to the base of the storage transistor for the purpose of inputing the information, which voltage is of such a type that the current necessary in order to interrupt the storage resistor can flow over the collector-emitter path. After the information has been input into the programmable read only memory, the task of this circuit arrangement is ended. Thus, it must be designed in such a way that the cost of additionally required structural elements is minimal, and that the operation of the read only memory is not impaired by its presence.